Marivibrio halodurans gen. nov., sp. nov., a marine bacterium in the family Rhodospirillaceae isolated from underground rock salt.

Gram-negative, spiral or curved rod-shaped cells of a bacterial strain, designated ZC80T, were isolated from a rock salt sample collected at Yunnan salt mine, China. Analysis of the strain's 16S rRNA gene sequence revealed a clear affiliation of this novel strain within the family Rhodospirillaceae. Strain ZC80T formed a robust cluster with Pelagibius litoralis CL-UU02T at a 16S rRNA gene sequence similarity level of 88.1 %. Strain ZC80T shared no more than 91.0 % 16S rRNA gene sequence similarity with the type strains of other species in the family Rhodospirillaceae. Strain ZC80T was able to grow in the presence of 2-15 % (w/v) NaCl, and grew at 10-50 °C and pH 6.0-10.0. The major fatty acids were C19 : 0 cyclo ω8c (41.3 %). The major isoprenoid quinone was ubiquinone 10 (Q-10). The major polar lipids were phosphatidylglycerol, phosphatidylethanolamine, diphosphatidylglycerol and an unidentified aminolipid. The DNA G+C content of strain ZC80T was 60.8 mol%. On the basis of phylogenetic analyses and chemotaxonomic and physiological data, strain ZC80T is considered to represent a novel species of a new genus in the family Rhodospirillaceae, for which the name Marivibrio halodurans gen. nov., sp. nov. is proposed. The type strain of Marivibrio halodurans is ZC80T (=CGMCC 1.15697T=NBRC 112461T).

Halorubrum salsamenti sp. nov., a Novel Halophilic Archaeon Isolated from a Brine of Salt Mine.

A non-motile, spherical or oval extremely halophilic archaeon, strain Y69T, was isolated from a brine of the Yunnan salt mine, China. Colonies on JCM 168 agar plate were round (1-2 mm in diameter), moist, and orange-pigmented. Phylogenetic analysis of the almost-complete 16S rRNA gene sequence showed that the isolate belonged to the species of the genus Halorubrum, with a close relationship to Halorubrum aidingense 31-hongT (98.5%), Halorubrum lacusprofundi ATCC 49239T (98.2%), and Halorubrum kocurii BG-1T (98.0%). The major polar lipids of strain Y69T were phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate and a sulfated diglycosyl diether. Strain Y69T grew in 15-30% (w/v) NaCl. The temperature and pH ranges for growth were 25-50 °C and 6.5-9.0, respectively. Optimal growth occurred at 20% (w/v) NaCl, 42 °C, and pH 8.0. Mg2+ was required for growth. The DNA G+C content was determined to be 65.1 mol% by the thermal denaturation method. DNA-DNA hybridization values between strain Y69T and the closely related species were lower than 70%. Based on the data presented in this study, strain Y69T represents a novel species for which the name Halorubrum salsamenti sp. nov. is proposed. The type of the strain is Y69T (=CGMCC 1.15455T = JCM 31270T).

Halobaculum roseum sp. nov., isolated from underground salt deposits.

Two extremely halophilic archaea, strains D90T and D93, were isolated from underground salt deposits of Yunnan salt mine, China. Both strains were pleomorphic or short rods, non-motile, Gram-negative and required 1.7 M NaCl for growth, with optimum at 3.4 M. Mg2+ was not required for growth. Multiple copies of the 16S rRNA gene were obtained for both strains. Sequence similarity analysis of 16S rRNA genes revealed that strains D90T and D93 were closely related to Halobaculum magnesiiphilum MGY-184T and Halobaculum gomorrense DSM 9297T with the sequence similarity between 96.2-98.1 %. The sequence similarity of the rpoB' gene between strain D90T and Halobaculum gomorrenseJCM 9908T was 94.1 %. The DNA G+C contents of strains D90T and D93 were 65.9 and 67.6 mol%, respectively. The major polar lipids of both strains were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester and glycolipid. The DNA-DNA relatedness value between strains D90T and D93 was 90.1±0.5 %, while that between strain D90T and Halobaculum gomorrenseJCM 9908T was 30.0±0.7 %. The comparison of physiological and biochemical characteristics, including the requirements of NaCl, Mg2+, pH, etc., differentiated strains D90T and D93 from Halobaculum magnesiiphilum MGY-184T and Halobaculum gomorrenseJCM 9908T. Therefore, strains D90T and D93 represent a novel species of the genus Halobaculum, for which the name Halobaculum roseum sp. nov. is proposed. The type strain is D90T (=CGMCC 1.15501T=JCM 31273T).

Halorubrum trueperi sp. nov., a halophilic archaeon isolated from a salt mine.

A novel, extremely halophilic archaeon, strain Y73T, was isolated from a salt mine in Yunnan, China. Colonies formed on solid medium were circular (2-3 mm in diameter), smooth, orange, glistening and convex (~1 mm in elevation). Cells were Gram-stain-negative, non-motile and pleomorphic. Mg2+ was required for growth (optimum at 0.05 M). Optimal growth was observed at 20 % (w/v) NaCl, 42-45 °C and pH 7.5-8.5 under aerobic conditions. 16S rRNA gene sequence comparison showed that strain Y73T was closely related to Halorubrum halophilum B8T (similarity: 98.1 %), Halorubrum lipolyticum 9-3T (97.9 %) and Halorubrum saccharovorum JCM 8865T (97.6 %). Levels of rpoB' gene sequence similarity between strain Y73T and H. halophilum B8T, H. lipolyticum 9-3T and H. saccharovorum JCM 8865T were 93.6, 93.8 and 94.7 %, respectively. DNA-DNA relatedness between strain Y73T and H. halophilum B8T was 38.7±0.5 %, while that between strain Y73T and H. saccharovorum JCM 8865T was 31.0±0.9 % . The DNA G+C content of strain Y73T was 61.9 mol%. The major polar lipids of strain Y73T were phosphatidic acid, phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester and phosphatidylglycerol sulfate as phospholipids, and sulfated diglycosyl diether-1 as glycolipid. The phenotypic, chemotaxonomic and phylogenetic properties suggest that strain Y73T represents a novel species, for which the name Halorubrum trueperi sp. nov is proposed. The type strain is Y73T (=CGMCC 1.15503T=JCM 31271T).

[Effects of methamidophos and 17beta-estradiol on the dynamics of experimental population of freshwater rotifer Brachionus calyciflorus].

The study on the dynamics of experimental population of freshwater rotifer Brachionus calyciflorus under exposure of different concentrations of methamidophos (0.01, 0.1, 1.0, 10.0, 100.0, 1000.0 and 10000.0 microg x L(-1)) and 17beta-estradiol (0.001, 0.01, 0.1, 1.0, 10.0, 100.0 and 1000.0 microg x L(-1)) showed that both methamidophos and 17beta-estradiol had significant effects on the mean growth rate of the population, but less affected the mean fertilization rate of mictic females. Methamidophos affected the mean ratio of ovigerous to non-ovigerous females and the mean mictic rate significantly but had less effect on the total resting egg production, while 17beta-estradiol was in adverse. Compared with the controls, both 10.0-10000.0 microg x L(-1) of methamidophos and 100.0 microg x L(-1) of 17beta-estradiol increased the mean population growth rate significantly. 0.1-10000.0 and 10.0 microg x L(-1) of methamidophos decreased significantly the average ratio of ovigerous to non-ovigerous females and the average mictic rate, respectively, and 1000.0 microg x L(-1) of 17beta-estradiol decreased the total resting egg production significantly. Within the range of test concentrations of methamidophos, the relationship between the mean population growth rate (Y, d(-1) and the concentration (X, microg x L(-1) of methamidophos could be described as Y = -2 x 10(-8) X2 + 0.002X + 0.374. The population growth rate could be used to assess the effects of methamidophos on the population dynamics of the rotifer.